Dragging equipment detector system



United States Patent G 2,993,117 DRAGGENG EQUIPMENT DETECTOR SYSTEMDonald D. Huffman, Penn Hills Township, Allegheny County, Pa., assignorto Westinghouse Air Brake Company, Wilmer-ding, Pa., a corporation ofPennsylvania FiledMar. 21-, 1960, Ser. No. 16,495 6 Claims. (Cl.246-169) My invention relates to dragging equipment detector systems forrailroads, and more particularly to circuits for use in connection withself-restoring dragging equipment detectors.

Self-restoring dragging equipment detectors are often disposed in thetrack ways of railroads to detect the presence of objects hanging ordragging from vehicles traversing the tracks. Such detectors are biasedto a normal or unactuated position and, after actuation thereof fromtheir normal position by hanging or dragging equipment, are restored bytheir biasing means to said normal position. A signal indication deviceis provided beyond the location of such a detector and is actuated bythe detector to give a suitable indication to the engineman of a trainwhen the detector is actuated by hanging or dragging equipment on thetrain. Since the detectors are self-restoring, means must be provided atthe location of a signal indication device to retain the draggingequipment indication until observed by the engineman, and for theengineman or other personnel to restore the indication device to itsnormal nonindicating condition after the train is stopped and thenecessary repairs made to the hanging or dragging equipment.

When a dragging equipment detector system such as that described isemployed in a stretch of single track railway over which trains may atdifferent times travel in either direction, and a single draggingequipment detector is employed for actuating a signal indication devicelocated in each direction beyond the device, means must be provided sothat only the indication device for the direction of travel of the trainoperating the detector is actuated, otherwise both indication deviceswould be actuated and it would be necessary for a maintainer or otherrailway employee to travel to the other indication device to restore itto its normal nonindicating condition. It is accordingly the object ofmy invention to provide, in a dragging equipment detector system of theclass outlined, and employed in conjunction with a railway signalingsystem for a stretch of single track in double direction runningterritory including means for providing following train movements, meansfor actuating the indication device for the direction of travel of atrain operating the dragging equipment detector, and means forpreventing actuation of the indication device for the opposite directionof travel.

Other objects and characteristic features of my invention will becomeapparent as the description proceeds.

In accomplishing the foregoing objects of my invention, I utilize thedirectional stick relays, employed for providing following trainmovements in single track double direction running railway territory, toprevent actuation of the dragging equipment indication device for theopposite direction of traflic from that in which a train actuating adragging equipment detector is traveling.

I shall describe one form of apparatus embodying my invention and shallthen point out the novel features thereof in claims.

In the accompanying drawings, FIGS. 1a and lb when placed side by sidewith FIG. la at the left and FIG. lb at the right comprise adiagrammatic view illustrating the track plan and the apparatus andcircuit arrangement of one system embodying my invention.

Referring to the drawings, there is shown a stretch of 2,993,117Patented July 18, 1961 "ice railway track provided with a simplifiedtypical three aspect automatic signal circuit arrangement of the typeoften employed in double direction running single track territory, suchas the single track between ends of a siding in centralized trafiiccontrol territory. Incorporated in the signaling system shown areprovisions for following train movements controlled by directional stickrelays at each signal location, as will be more fully pointed out laterin this description. It will be understood by those skilled in the artthat in such signaling arrangements as that shown, provisions are madefor establishing, maintaining, and changing the direction of t'r'aflicbetween stations or ends of siding, but these means are not shown in thedrawings since they form no part of my present invention.

Referring to the drawings in more detail, there is shown at the upperportion thereof a stretch of railway track extending from west to east,or from left to right as shown on the drawings, between two pointsdesignated by the reference characters A and C. This stretch of railwaytrack comprises left-hand and right-hand track sections designated 2Tand 3T, respectively separated from each other at a point B,intermediate points A and C, by insulated joints J. The stretch ofrailway track A==C is also separated by insulated joints J from tracksections designated IT and 4T located to the left and right of thestretch, respectively.

Each track section is provided with a track circuit including a sourceof energy connected across the rails at one end and a track relayconnected across the rails at the other end in the manner well known inthe art, such that the track relays are energized when no train occupicsthe respective track section. The sources of track circuit energy fortrack sections 2T and ST are shown as batteries designated 2TB and 3TB,respectively, and the track relays for track Sections 1T, 2T, 3T and 4Tare designated ITR, 2TR, 3TR and 4TR, respectively. For purposes ofsimplicity, the sources of track circuit energy for track sections ITand 4T are not shown in the drawings, but it will be understood theyeach may be a battery similar to that shown for track sections 2T and3T.

An entering signal and a leaving signal for governing train movementsinto and out of the track stretch A-C at the left-hand end thereof arelocated adjacent the insulated joints at point A. These leaving andentering signals are designated 1G and 2G, respectively. Similarly anentering signal and a leaving signal designated 36 and 46, respectively,are located adjacent the insulated joints at point C for governing trainmovements intoand out of the track stretch A-C at the right-hand endthereof. These signals may be of any suitable type and each signal ashere shown is of the type commonly known as a color-light signal.Signals 1G, 2G, 3G and 4G are shown in the lower portion of the drawingsas each having a green lamp, a yellow lamp, and a red lamp designatedGE, YE, and RE, respectively, each lamp designation being prefixed bythe number of its respective signal. These lamps when illuminatedindicate clear; approach, prepare to stop at next signa; and stop,respectively. Signals 1G and 4G are also each provided with anadditional indication lamp designated IDEK and 4DEK, respectively. Thepurpose of these additional lamps will be pointed out later in thisdescription.

As shown in the upper right-hand portion of FIG. la, there is located inthe vicinity of point B in the track stretch A--C a dragging equipmentdetector of the selfrestoring type and designated DED. The details ofthis detector form no part of my present invention and, therefore, arenot shown in the drawings. However, for the purposes of thisdescription, the detector may be similar to that shown in Letters Patentof the United States No.

2,677,048, issued April 27, 1954, to Robert A. Woods and Herbert L. Bonefor a Dragging Equipment Detector, but any other similar detector may beemployed with my invention. It is considered sufiicient for the purposesof this description to point out that the detector comprises upstandingdetector plates supported on a shaft extending between and beyond therails and arranged so as to be deflected from their upright positionwhen struck by an object hanging or dragging from a vehicle traversingthe rails in either direction. The detector plates are biased to theirnormal or upright position, and accordingly when they are deflected,they return to their normal or nnactuated position as soon as thedragging object clears the detector. Such detectors are, therefore,termed self-restoring detectors. The shaft which supports the detectorplates'is operatively connected with a plurality of contacts which arearranged to be normally closed when the plates are in their unactuatedor upright position, and to be opened when the detector plates aredeflected or actuated. On FIG. 1a of the drawings two such contactsdesignated a and b are shown in the conventional manner below thedetector and indicated as controlled thereby by the dotted lineextending from the detector to the contacts. It will be readilyapparent, however, that the detector could be provided with but one suchcontact, and a repeater relay or relays could be controlled by a circuitover that single contact.

It should be pointed out at this time that a suitable source of controlcurrent is provided at each of the locations" A and C, these sourcesbeing preferably a battery of proper voltage and capacity. However, forthe sake of simplicity these sources are not shown in .the drawings, butthe positive and negative terminals of the source at location A aredesignated B1 and N1, re-

spectively; and the positive and negative terminals of the source atlocation C are designated B2 and N2, respectively.

Located at the signal locations at points A and C are :a signal controlrelay and a directional stick relay associated with each of the signals.These signal control and directional stick relays are designated by thereference characters HDR and SR, respectively, each designation beingprefixed by the number 1, 2, 3 or 4, indicating the number of the signalwith which the relay is associated. There are also located at points Aand C dragging equipment detector repeater relays designated lDEDSR and4DEDSR, respectively, and manually operable circuit controllers 1PB and4PB, respectively. These con- .trollers are here shown as manuallyoperable push buttons each biased to a first or normal position by aspring indicated by the letter S on an extension of the button andactuable to a second or actuated position, when depressed to close anormally open contact a. The direction of depression of the buttons toclose contacts a is indicated by the arrow heads shown below the movableportion of the contacts, and springs S operate to return the buttons totheir normal position and open the contacts when the buttons are nolonger depressed. Such push buttons are well known in the art.

The aforesaid relays 18R, 28R, 38R, 4SR, lDEDSR and 4DEDSR may be of thewell known neutral type each having a plurality of front and backcontacts opened and closed, respectively, and closed and opened,respectively, according as the relay is deenergized or energized,respectively.

Relays IHDR, ZHDR, SHDR and 4HDR may be of the conventional retainedneutral polarized type as substantially shown, the polarized feature ofthe relay being indicated by the letter P in the rectangle representingthe winding of the relay. Such relays are provided with a polarizedarmature and a neutral ararnature each controlling one or more contacts.The movable portion of the contacts controlled by the polarized armatureof the relays are shown in a vertical line on the drawings and areoperated to close with a normal or left-hand contact point when positiveand negative energy are supplied to the left-hand and right-handterminals, respectively, of the control windings of the relays, and toclose with a reverse or right-hand contact point when positive andnegative energy are supplied to the right-hand and lefthand terminals,respectively, of said control windings. A retained-neutral polarizedelay is termed retainedneutral because the neutral armature of such arelay does not release if the polarity of the energy supplied to thecontrol winding of the relay is quickly reversed. That is, the neutralarmature of such a relay will remain picked up and the neutral frontcontacts consequently closed during the period of movement of the relayspolar contacts from normal to reverse or reverse to normal upon quickreversal of polarity of the energy supplied to the control winding ofthe relay. This feature is indicated on the drawings by a downwardlypointing arrowthrough the neutral contacts of the relays, therebyindicating, in the conventional manner, that these are slow to release.Such relays are well known in the art and may, for example, be similarto that shown in Letters Patent of the United States, No. 2,363,038,issued November 21, 1944, to Selden B. Aylsworth for an ElectricalRelay.

I will first outline in detail the control circuits for the aforesaidsimplified typical automatic signal circuit arrangement and will thenoutline in detail the control circuits for the apparatus of my inventionemployed in conjunction with such a signaling arrangement.

Signal control relay 2HDR in FIG. la has a normal control circuitextending from battery terminal B2 in FIG. lb over the front point ofcontact b of relay 4HDR, front contact b of relay 3TR, conductor 8,front contact b of relay ZTR in FIG. 1a, the left-hand terminal of thewinding of relay ZI-I-DR, the right-hand terminal of the winding ofrelay ZHDR, conductor 7, and over the front point of contact a of relay4HDR in FIG. lb to battery terminal N2.

Relay ZHDR has a reverse control circuit which extends from batteryterminal B2 in FIG. 1b over front contact b of relay 4SR, the back pointof contact a of relay 4HDR,

.conductor 7, the right-hand terminal of the winding of relay ZHDR inFIG. la, the left-hand terminal of the winding of relay ZHDR, frontcontact b of relay ZTR, conductor 8, front contact b of relay 3TR inFIG. lb, the back point of contact b of relay 4HDR, and over frontcontact 0 of relay 4SR to battery terminal N2. It is thus apparent thatrelay ZHDR is deenergized when either of the track sections 2T or 3T areoccupied, or when relays 4HDR and 4SR are both deenergized. Relay ZHDRis energized by current of normal polarity, that is, current of thepolarity to control the polar contacts of the relay to their normal orleft-hand position when relay 4HDR is energized as hereinafterdiscussed; and is energized by current of reverse polarity, that is,current of the polarity to control the polar contacts of the relay totheir reverse or right-hand position when relay 4HDR is deenergized andrelay 4SR is energized as hereinafter described.

Signal control relay 3HDR in FIG. lb has a normal control circuit whichextends from battery terminal B1 in FIG. 1a over the front point ofcontact a of relay lHDR, front contact a of relay ZTR, conductor 5,front contact a of relay 3TR in FIG. lb, the left-hand terminal of relay3HDR, the right-hand terminal of relay 3HDR, conductor 6, and over thefront point of contact b of relay IHDR to battery terminal N1.

Relay 3HDR has a reverse control circuit which may be traced frombattery terminal B1 in FIG. la over front contact 0 of relay ISR, theback point of contact I) of relay lI-IDR, conductor 6, the right-handterminal of relay SHDR in FIG. lb, the left-hand terminal of relay 3HDR,front contact a of relay 2TR, conductor 5, front contact a of relay ZTRin FIG. 1a, the back point of contact a of relay IHDR, and over frontcontact b of relay 18R to battery terminal N1. Thus, relay SHDR isdeenergized when either of the track sections .21 or .31" are occupied,or when relays :IHTDR and 18R are both deenergized. Relay 3I-lDR isenergized by current of normal polarity, that is current of the polarityto control the polar contacts of the relay to their normal or left-handposition when relay IHD'R is energized as hereinafter discussed; and isenergized by current of reverse polarity, that is, current of thepolarity to control the polar contacts of the relay to their reverse orright-hand position, when relay lHDR is deenergized and relay 15R isenergized as hereinafter described.

For purpose of simplicity the control circuits for relays lHDR and 4HDRare not shown in the drawings but relay lI-IDR is indicated ascontrolled by traffic conditions west of signal 1 and relay 4HDR isindicated as controlled by traflic conditions east of signal 4. RelayIHDR is controlled from the first westbound signal location to the westof signal 16 by circuits similar to that shown for control of relaySHDR, and relay 4HDR is controlled from the first eastbound signallocation to the east of signal 4G by circuits similar to that shown forcontrol relay ZHDR. This will be apparent to those skilled in the art,and, therefore, it is not necessary to show the circuits for control ofrelays 'IHDR and 4HDR.

It will also be apparent to those skilled in the art that in a signalingsystem such as shown in the drawings, the first eastbound signal to thewest of signal 2G and the first westbound signal to the east of signal3G will be controlled from locations A and C, respectively, in a mannersimilar to that shown for control of signals 16 and 36, respectively.However, since these control circuits are not necessary to make thedescription complete, the circuits have been omitted from the drawingsand only those circuits necessary for an understanding of my inventionhave been shown.

As previously mentioned, directional stick relays 15R and 25R in FIG. 1aprovide for following train move ments in the signaling system shown, aswill be more fully discussed later in this description. Relay 18R has apickup circuit which extends from battery terminal B1 over back contacta of relay lTR, the front point of contact of relay lHDR, and throughthe winding of relay 18R to battery terminal N1. Relay ISR has a firststick circuit which extends from battery terminal B1 over back contact aof relay lTR, front contact a of relay 18R, and through the winding ofrelay 18R to battery terminal N1. Relay 15R has a second stick circuitwhich extends from battery terminal B1 over the back point of contact 0of relay lHDR, front contact a of relay 15R, and through the winding ofrelay 18R to battery terminal N1. Thus, relay 15R is energized whensignal 16 is controlled, by the energization of relay IHDR, to give aclear or proceed indication and relay ITR is thereafter released by atrain accepting signal 16. Relay lSR is thereafter maintained energizedso long as relay ITR remains released or so long as relay lHDR remainsdeenergized after the acceptance of signal 16 by the train.

Relay 28R has a pickup circuit which extends from battery terminal B1over back contact 0 of relay ZTR, the front point of contact a of relayZHDR, and through the winding of relay 2SR to battery terminal N1. Relay28R has a first stick circuit which extends from battery terminal B1over back contact c of relay ZTR, front contact a of relay 28R, andthrough the winding of relay 2SR to battery terminal N1. Relay ZSR has asecond stick circuit which extends from battery terminal Bl over theback point of contact a of relay ZHDR, front contact a of relay 28R, andthrough the winding of relay 28K to battery terminal N1. Thus, relay ZSRis energized when signal 26 is controlled, by the energization of relayZHDR, to give a clear or proceed indication and relay ZTR is thereafterreleased by a train accepting signal 2G. Relay 28R is thereaftermaintained energized so long as relay 2TR remains released or so long asrelay ZHDR remains deenergized after the acceptance of signal 2G by thetrain.

Directional stick relays 38R and 4SR in FIG. 1b, as previouslymentioned, also provide for following train movements in the signalingsystem shown. This will be more fully pointed out hereinafter in thisdescription. Relay 3SR has a pickup circuit which extends from batteryterminal B2 over back contact 0 of relay 3TR, the front point of contacta of relay 3l-IDR, and through the winding of relay 38R to batteryterminal N2. Relay 3SR has a first stick circuit which may be tracedfrom battery terminal B2 over back contact c of relay 3TR, front contacta of relay 38R, and through the winding of relay 38R to battery terminalN2. Relay 38R has a second stick circuit which may be traced frombattery terminal B2 over the back point of contact a of relay 3HDR,front contact a of relay 38R, and through the winding of relay 38R tobattery terminal N2. By these circuits relay SSR is energized whensignal 36 is controlled, by the energization of relay 3HDR, to give aclear or proceed indication and relay 3TR is thereafter released by atrain accepting signal 3G. Relay SSR is thereafter maintained energizedso long as relay 3TR remains released or so long as relay 3HDR remainsdeenergized after acceptance of signal 36 by the train.

Relay 48R has a pickup circuit extending from battery terminal B2 overback contact a of relay 4TR, the front point of contact c of relay 4HDR,and through the winding of relay 48K to battery terminal N2. Relay 48Rhas a first stick circuit which extends from battery terminal B2 overback contact a of relay 4TR, front contact a of relay 48R, and throughthe winding of relay 48K to battery terminal N2. Relay 45R has a secondstick circuit which extends from battery terminal B2 over the back pointof contact c of relay 4HDR, front contact a of relay 48R, and throughthe winding of relay 48R to battery terminal N2. Thus, relay 48R isenergized when signal 4G is controlled, by the energization of relay4HDR, to give a clear or proceed indication and relay 4TR is thereafterreleased by a train accepting signal 46. Relay 48R is thereaftermaintained energized so long as relay 4TR remains released or so long asrelay 4HDR remains deenergized after acceptance of signal 4G by thetrain.

The circuits for illuminating the lamps of signals 16 and 26 are shownat the bottom of FIG. 1a and will now be traced in detail. The greensignal lamp 1GB of signal 1G has an energizing circuit which extendsfrom battery terminal B1 over the front point of contact d of relay IHDR, polar contact e of relay IHDR in its lefthand or normal position,and through the filament of lamp 1GB to battery terminal N1. The yellowsignal lamp lYE of signal 1G has an energizing circuit which extendsfrom battery terminal B1 over the front point of contact d of relay1=HDR, polar contact e of relay IHDR in its right-hand or reverseposition and through the filament of lamp 1YE to battery terminal N1.The red signal lamp IRE of signal 1G has an energizing circuit extendingfrom battery terminal B1 over the back point of contact a of relayll-IDR and through the filament of lamp I'RE to battery terminal N1.

As previously mentioned signal 16 is provided with an additionalindication lamp IDEK. The circuit for energizing this lamp extends frombattery terminal B1 over back contact b of relay IDEDSR, to be describedin detail hereinafter, and through the filament of the lamp to batteryterminal N1.

The green signal lamp 2GB of signal 26 has an energizing circuit whichmay be traced from battery terminal B1 over the front point of contact12 of relay ZHDR, polar contact c of relay 2 HDR in its normal orlefthand position, and through the filament of lamp 2GB to batteryterminal N1. Yellow signal lamp 2YE of signal 2G has an energizingcircuit extending from battery terminal B1 over the front point ofcontact b of relay ZHDR, polar contact of relay ZHDR'in its reverse orright-hand position and through the filament of lamp '2YE to batteryterminal N1. The red signal lamp ZRE has an energizing circuit whichextends from battery terminal B1 over the back point of contact b ofrelay ZHDR and through the filament of lamp ZRE to battery terminal N1.

The circuits for illuminating the lamps of signals 3G and 46 are shownat the bottom of FIG. 1b and will now be traced in detail. Green signallamp 3GB of signal 36 has an energizing circuit extending from batteryterminal B2 over the front point of contact b of relay 3HDR, polarcontact c of relay SHDR in its left-hand or normal position, and throughthe filament of lamp 3GB to battery terminal N2. The yellow signal lamp3YE of signal 36 has an energizing circuit which extends from batteryterminal B2 over the front point of contact b of relay SHDR, polarcontact 0 of relay 3HDR in its right-hand or reverse position, andthrough the filament of lamp 3YE to battery terminal N2. The energizingcircuit for red lamp 3RE of signal 36 extends from battery terminal B2over the back point of contact b of relay SHIDR, and through thefilament of lamp 3RE to battery terminal N2.

The green signal lamp 4GB of signal 4G is provided with an energizingcircuit extending from battery terminal B2 over the front point ofcontact 0! of relay 4HDR, polar contact e of relay 4HDR in its normal orleft-hand position, and through the filament of lamp 4GE to batteryterminal N2. Yellow signal lamp 4YE of signal 4G has an energizingcircuit which extends from battery terminal B2 over the front point ofcontact d of relay 4HDR, polar contact e of relay 4HDR in its reverse orright-hand position, and through the filament of lamp 4YE to batteryterminal N2. The energizing circuit for red signal lamp 4RE of signal 4Gextends from battery terminal B2 over the back point of contact (I ofrelay 4HDR and through the filament of lamp 4RE to battery terminal N2.

Similarly to signal 16 and as previously mentioned, an additionalindication lamp 4DEK is provided on signal 4G. The circuit forenergizing this lamp extends from battery terminal B2 over back contactb of relay 4DEDSR, to be described in detail hereinafter, and throughthe filament of the lamp to battery terminal N2.

In accordance with my invention I provide in conjunction with theabove-described signaling circuits, the previously mentioned draggingequipment detector repeater relays IDEDSR and 4DEDSR, and controlcircuits therefor, at locations A and C, respectively. Theaforementioned dragging equipment detector DED having normally closedcontacts a and b is provided in the vicinity of location B intermediatelocations A and C. .I will first describe in detail the control circuitsfor relays IDEDSR and 4DEDSR, and will then outline, under specificexamples of train movements, the operation of the apparatus of myinvention in conjunction with the typical railway signaling apparatusshown.

Relay IDEDSR in FIG. 1a has an energizing circuit which extends frombattery terminal B1 over contact a of push button 1PB, closed only whenthe button is depressed, and through the winding of relay IDEDSR tobattery terminal N1. Relay lDEDSR has a first hold ing circuit whichextends from battery terminal B1 over conductor 9, contact a of detectorDED, closed when the detector is in its unactuated or upright position,conductor 10, front contact a of relay IDEDSR, and through the windingof relay lDEDSR to battery terminal N1. Relay IDEDSR has a secondholding circuit extending from battery terminal B1 over front contact bof relay 2SR,front contact a of relay lDEDSR, and through the winding ofrelay IDEDSR to battery terminal N1.

Relay 4DEDSR in FIG. lb has an energizing cir- -cuit extending frombattery terminal B2 over contact a depressed, and through the winding ofrelay 4DEDSR to battery terminal N2. Relay 4DEDSR has a first holdingcircuit which may be traced from battery terminal B2 over conductor 12,contact b of detector DED, closed when the detector is in its normal orupright position, conductor 11, front contact a of relay 4DEDSR, andthrough the winding of relay '4DEDSR to battery terminal N2. Relay4DEDSR'has a second holding circuit'which extends from battery terminalB2 over front contact b of relay 38R, front contact a of relay 4DEDSR,and through the winding of the relay to battery terminal N2.

From the above traced control circuits for relays IDEDSR and 4DEDSR itis apparent that these-relays are normally energized and oncedeenergized cannot be reenergized until the push button associated witheach respective relay is depressed. In order that only the DEDSR relayfor the direction of movement of a train will be released when draggingequipment on the train actuates detector DED, a front contact of thefollowingmove directional stick relay, associated with the signal whichgoverned the entry of the train into the track stretch, is employed tomaintain the other DEDSR relay energized. Otherwise, both DEDSR relayswould be released and both push buttons IPB and 4PB would have to beactuated to reenergize each respective DEDSR relay.

All the relays are shown in the drawings in the positions which theyoccupy when the established direction of tratfic through the railwayterritory provided with the signaling system shown is from West to eastor from left to right as shown on the drawings, and no trains haveproceeded by signal 2G. Under these conditions all the directional stickrelays SR and signal control relays lHDR and 3HDR are deenergized,relays IDEDSR and 4DEDSR are energized, and relays Zl-IDR and 4HDR areenergized and have their polar contacts controlled to their normal orleft-hand position by the closure of the previously discussed normalcontrol circuits for these relays. As stated, the direction of traificbeing shown as established for the eastbound direction, relay lI-IDRwill be deenergized at this time and the control circuits for relay 3HDRwill be opened at front contacts a and b of relay lHD-R and frontcontacts b and c of relay 1SR.

Each of the signals 2G and 4G is at this time displaying its greensignal lamp to give a clear indication, and relays iHDR and 3HDR beingdeenergized at this time, the red signal lamps for signals 16 and 36 areilluminated.

I will now describe the operation of the apparatus of my invention whenan eastbound train accepts the clear indication given by the illuminatedgreen lamp 2GB and enters the track stretch A-C, and dragging equipmenton the engine or a car of the train actuates the dragging equipmentdetector DED.

When the eastbound train accepts cleared signal 2G and enters tracksection 2T, relay 2TR is released, and opens its front contact b in thecontrol circuit for relay 2HDR and closes its back contact c to closethe pre viously described energizing circuit for relay ZSR including theback contact c of relay ZTR and the front point of contact a of relay2HDR. Relay 2HDR, as previously pointed out, is slow to release andretains the front point of its contact a closed for a suflicient periodof time, after the opening of its control circuit at front contact b ofrelay 2TR, to permit back contact 0 of relay 2TR to close and completethe pickup circuit for relay 25R. The energization of relay 25R closesat its own front contact a the first stick circuit for maintaining therelay energized over the back point of contact c of relay 2TR whiletrack section 2T is occupied. When the slow release period of relay ZHDRhas expired, that relay releases to establish the second stick circuitfor relay 2SR including the back point of contact a of relay ZHDRartisan? circuit serves to maintain relay 28R energized when the trainvacates track section 2T, but continues :to occupy track section 3T,since the energizing circuit for relay 2HDR remains open at frontcontact b of relay SIR at this time.

The energization of relay 28R as described above closes the previouslydescribed second holding circuit :for relay l-DEDSR including frontcontact b of relay 28R. Relay iDEDSR will thus be energized so long asrelay 28R is energized.

When the previously mentioned dragging equipment on the engine or car ofthe train actuates the detector plates of dragging equipment detectorDED, contacts a and b of the detector DED are momentanily'opened untilthe dragging object clears .the detector. The momentary opening ofcontact a of detector DED opens the previously described first holdingcircuit .for relay IDEDSR, but the second holding circuit for that relaybeing closed at front con-tact b of relay 25R, relay I'DEDSR remainsenergized. The momentary .opening of contact I) of detector DED opensthe previously described first holding circuit for relay dD EDSR and,the second holding circuit for that relay over front contact 12 of relay45R being open at this time, relay 4DEDSR releases, opening its frontcontact a in its previously described holding circuits. When contact -bof detector DED closes, after the dragging object clears theselfrestoring detector, the holding circuits for relay 4DEDSR remainopen at front contact a of relay '4DEDSR and the relay remains in itsreleased position.

The release of relay 4DEDSR closes the previously described circuit forillumination of the signal lamp 4DEK of signal 46. This circuit extendsfrom battery terminal B2 over back contact b of relay -4DEDSR andthrough the filament of the lamp to battery terminal N2. Thus, lamp4DE-K is illuminated to give an indication to the engineman of the trainthat the train has hanging or dragging equipment and must be stopped forrepairs. The dragging equipment indication may by operating rules bemade an absolute stop indication or, by obvious circuitry not shown inthe drawings, the red signal lamp 4RE of signal 46 may be illuminated inconjunction with lamp 4DEK.

As is apparent, there must be sufiicient distance between signal 4G andthe location of the dragging equipment detector that the entire lengthof the longest train to traverse track stretch A-C is past the detectorbefore the engine of the train passes signal 4G, otherwise no indicationwill be given to the engineman *of the train when equipment is hangingor dragging from :that part of the train not yet by the detector. Thiscondition is also applicable to the distance between signal 16 and thelocation of the detector, as is believed obvious.

When the dragging equipment on the train has been removed or repaired,the engineman or other railway personnel may depress push button APB toreenergize relay 4DEDSR over its previously described pickup circult andthe train may then proceed in its eastbound direction.

When the train passes signal 46, following-move directional stick relay48R is energized over its previously described pickup circuit. Theenergization .of relay 48R prepares at its front contacts b and c thereverse control circuit for relay ZHDR. When the train vacates tracksection 2T, relay ZTR will pick up and complete at its from contact bthe reverse control circuit for relay ZHDR at location A. The closing ofthe front -.point of contact b of relay ZHDR and the reverse point ofthe polar contact c of relay ZHDR will close the previous-1y describedenergizing circuit for yellow'signal lamp 2YE of signal 26, and afollowing train may enter track section 2T. This is the-usual operationin railway signaling systems having provisions for following trainmovements, such as the system shown in the drawings.

When the established direction of traffic through the railway territoryprovided with :thesignaling system shown is in :the westward directionor from right to left as shown on the drawings, and ;-no trains haveproceeded by signal 36, all the directional stick relays ,SR and signalcontrol relays ZH'DR and 4HDR are deenergized, relays i'DED'SR and4DEDSR are energized, and relays IHDR and SHDR are energized and havetheir polar contacts controlled to their normal or left-hand position bythe closure of thepreviously discussed normal 'control circuits forthese .relays. :However, the operation of the apparatus for a westboundtrain moving through the track stretch and having dragging equipmentbeing similar to that just described for an eastbound train, :nodescription of the "operation of the apparatus and circuitry for thewestbound train movement is believed necessary.

From the foregoing description it is apparent that, with the arrangementof apparatus of my invention as'shown in the drawings of thisapplication, I have provided, .in conjunction with an automaticsignaling system .for a stretch of double direction running single trackrailway having provisions for following train movements, means foremploying a single dragging equipment detector to detect objects hangingor dragging from trains moving over the stretch in either direction andto provide a dragging equipment indication for only the direction inwhich a train actuating the detector is moving. This opera tion of theapparatus of my :invention is accomplished without additional :means forindicating the direction of train movements, by "making use of existingdirectional indicating means employed for following trainmovements inrailwaysignaling system of the type described.

While I have shown and described only one form .of apparatus embodyingmy invention, it should be understood that various changes andmodifications may be made therein within the scope of the appendedclaims and without departing from the spirit and scope of my invention.

Having'thus described my'invention, 'what I claim is:

1. In astretch of railway track provided with a pair of entering andexit signals at each 'end for governing train movements into and out ofthe stretch, a directional stick relay associated witheach pair ofsignals, and means. for energizing each stick relay when its associatedenter ing signal is cleared for a train movement and a train accepts thecleared signal; the combination comprising, a self-restoring draggingequipment detector in said stretch operable "to two extreme positionsand normally biased to an intermediate position, a plurality of normallyclosed contacts, means controlled by said detector for opening saidcontacts when the detector is operated from its biased position, a pushbutton associated with each pair of signals and normally biased to afirst position and manually operable to a second position, a repeaterrelay associated with each push button, means controlled by each pushbutton in its operated position for energizing the associated repeaterrelay, means controlled by said contacts in their closed position formaintaining each repeater relay energized when once energized .byoperation of the associated push button, means controlled by each saiddirectional stick relay in its energized position for maintaining theassociated repeater relay energized when once energized by operation ofthe associated push .button, an indication device associated with eachrepeater relay and mounted on the .associated exit signal, and meanscontrolled by :each repeater relay in'its deenergized position forcontrolling the associated indication device to display a draggingequipment indication.

2. %In a stretch of railway track provided with first and second pairsof entering and exit signals at first and second ends .of the stretchrespectively, for governing train movements into and out of the stretch,a directional stick relay associated with each pair of signals, andmeans for energizing each directional stick relay when its associatedentering signal is cleared for a train movement into the stretch and atrain accepts the cleared signal; the combination comprising, aself-restoring dragging equipment detector in the trackway of saidstretch and operable to two extreme positions and normally biased to anintermediate position, a plurality of contacts associated with saiddevice and normally in a closed position and operable to an openposition when the device is operated from its intermediate position, afirst detector relay associated with the directional stick relayassociated with the first pair of signals, a second detector relayassociated with the directional stick relay associated with the secondpair of signals, a manually operable circuit controller associated witheach detector relay, means controlled by each said circuit controllerfor energizing the associated detector relay when the controller isoperated, means controlled by the associated stick relay for maintainingthe first detector relay energized when once energized and the stickrelay is energized, means controlled by the associated stick relay formaintaining the second detector relay energized when once energized andthe stick relay is energized, means controlled by said contacts in theirclosed position for maintaining said detector relays energized when onceenergized, a first dragging equipment indicator associated with thefirst detector relay and its associated leaving signal, a seconddragging equipment indicator associated with the second detector relayand its associated leaving signal, and means controlled by each detectorrelay for controlling the associated indicator to give a draggingequipment indication when the detector relay is deenergized.

3. In a stretch of railway track provided with first and second pairs ofentering and exit signals at first and second ends of the stretchrespectively, for governing train movements into and out of the stretch,a stick relay associated with each pair of signals, and means forenergizing each stick relay when its associated entering signal iscleared for a train movement into the stretch and a train passes thesignal and for maintaining the relay energized so long as the trainoccupies the stretch;

the combination comprising, a self-restoring dragging equipment detectorin the trackway of said stretch biased to a normal position and operablefrom that position; a plurality of contacts associated with said deviceand normally in a closed position and operable to an open position whenthe device is operated, a device repeater relay associated with eachstick relay and its associated pair of signals, a manually operablecircuit controller for each device repeater relay, each controllerhaving a normally open contact operable to a closed position when thecontroller is operated, means controlled by each coni troller contact inits closed position for energizing the associated device repeater relay,means controlled by a front contact of each stick relay in its closedposition for maintaining the associated device repeater relay energizedwhen once energized, means controlled by said contacts associated withsaid device in their closed position for maintaining each devicerepeater relay energized when once energized, a dragging equipmentindication device associated with each said leaving signal and itsassociated device repeater relay, said devices normally giving noindication and capable of giving a dragging equipment indication whenactuated, and means controlled by a closed back contact of each devicerepeater relay for actuating the associated indication device.

4. In a stretch of railway track provided with first and second pairs ofentering and exit signals at first and second ends of the stretchrespectively, for governing train movements into and out of the stretch,a stick relay associated with each pair of signals, means for energizingeach stick relay when its associated entering signal is cleared for atrain movement into the stretch and a train passes the signal, and meansfor maintaining each stick relay energized when once energized so longas the train occupies the track stretch; the combination comprising, aself-restoring dragging equipment detector disposed in the trackway ofsaid stretch and normally biased to an unoperated position, a pluralityof contacts closed when and only when the device occupies its unoperatedposition, a detector repeater relay associated with each said leavingsignal and the associated stick relay, a manually operable contactassociated with each detector repeater relay, each contact normallybiased to an open position and manually operable to a closed position, apickup circuit for each said repeater relay including its associatedmanually operable contact, a first stick circuit for each said repeaterrelay including a front contact of its associated stick relay, a secondstick circuit for each said repeater relay including one of its ownfront contacts and one of said detector contacts, a dragging equipmentindication device associated with each said leaving signal and operablewhen energized to give a dragging equipment indication, and anenergizing circuit for each said indication device including a backcontact of the associated detector repeater relay.

5. In combination with a stretch of railway track extending betweenfirst and second locations, a pair of entering and leaving signals ateach said location for governing train movements into and out of thestretch respectively, track occupancy detection means for said stretch,a stick relay associated with each said pair of signals, a signalcontrol relay for each said entering signal, means controlled by eachsaid control relay and said track occupancy detection means forenergizing the associated stick relay when the associated enteringsignal is cleared to permit a train to move into the stretch and thetrain passes that signal, means controlled by said track occupancydetection means for maintaining each energized stick relay energized solong as the train occupies the track stretch, a self-restoring draggingequipment detector biased to a normal position and disposed in thetrackway of said stretch, a detector repeater relay at each of saidfirst and second locations, a manually operable circuit controllerassociated with each of said repeater relays and biased to a normalposition, means controlled by each said controller for energizing saidassociated detector repeater relay when the controller is operated,means controlled by each said stick relay for maintaining the associateddetector repeater relay energized when once energized and the stickrelay is en ergized, means controlled by said detector in its saidnormal position for maintaining each detector repeater relay energizedwhen once energized, a dragging equipment indication lamp on each saidleaving signal, and means controlled by each said detector repeaterrelay for energizing the associated indication lamp when the repeaterrelay is deenergized.

6. A directional dragging equipment detector system for a stretch oftrack having an exit signal and an entering signal at each end, adirectional stick relay associated with each entering signal, and meansassociated with each entering signal and controlled by the entrance of atrain into said stretch for energizing the associated stick relay;comprising, in combination, a self-restoring dragging equipment detectordisposed in the trackway of said stretch, a dragging equipmentindication lamp on each said exit signal, means controlled by saiddetector and said stick relays for energizing only that indication lampat the exit end of the stretch for a train when dragging equipment onthe train actuates the detector, a manually operable circuit controllerat said exit end of the stretch, and means controlled by said circuitcontroller for deenergizing the energized indication lamp when thecontroller is operated following a pe riod of energization of the lamp.

No references cited.

